This is very useful when you there's so much to learn. First:

1. Make a list of what you're going to study
2. Identify easy topics/short topics
3. Try to finish the easier ones or shorter ones
4. Move on to the bigger/harder topics
5. If possible, divide the bigger topic into 2 parts and learn it based on your capability (videos, blogs, explaining to someone else, etc.)
6. Take a break. This is important! Refresh your brain. Go read a book or watch an episode.
7. Get back to studying. Try finishing 80% of the list you've written in step 1.
8. Reward yourself if you finish the 20% as well! Congrats!

This is a favorite retaining method by Elon Musk. When you learn something new, it's completely normal to forget it after some time. One way you can remember this is connecting what you've learned with your previous knowledge. Meaning, you can try and think about how this new knowledge can be applied in your real-life or incidents that have happened in the past.

Studies have shown that if you cannot explain something to a person, it means you have not understood the topic yourself. Try and teach your friends what you've learned. This can help you simplify your words and you can see the areas that you've forgotten. If you don't have a friend, you can explain it to your pillow.